On Sunday, France’s education minister announced that mobile phones will be banned from primary, junior, and middle schools, calling it a matter of “public health.” While phones are already prohibited in classrooms in France, starting in September 2018 students won’t be allowed to use them on breaks, at lunch, or between lessons either. “These days, the children don’t play at break time anymore,” Jean-Michel Blanquer said, according to the Local, an English-language publication. “They are just all in front of their smartphones and from an educational point of view, that’s a problem.”

Emmanuel Macron, France’s young new president, proposed a similar ban in his campaign earlier this year. Former New York City mayor Michael Bloomberg also attempted a cellphone ban in 2006, but parents complained of inconsistent enforcement, and that they couldn’t contact their kids. Bill de Blasio, Bloomberg’s successor, lifted that ban in 2015, citing inequity (the policy was more heavily used in schools with metal detectors, which tend to be poorer). Now New York City principals devise their own mobile phone policies, or default to the standard: Students can bring their phones to school but have to keep them out of sight.

Research is on Bloomberg—and the French government’s—side. According to a 2015 working paper (pdf) published by the London School of Economics, schools that banned mobile phones saw test scores for their 16-year-olds improve by 6.4%, or the equivalent of adding five days to the school year. “We found that not only did student achievement improve, but also that low-achieving and low-income students gained the most,” economists Philippe Beland and Richard Murphy told the BBC.

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It’s not yet clear how the French ban will work but, according to the Guardian, no one is happy about it, including the teachers union, parents, and (naturally) students. Teachers are concerned they’ll be required to search students to make sure they have left all phones in their lockers.

“How is the school going to stock them? And how are they going to make sure they’re given back to the owner at the end of school?” asked Gérard Pommier, head of the Federation of Parents in State Schools. (In New York City, a cottage industry of cellphone storage popped up, charging students about $1 a day. Perhaps France will have to do the same, and Macron can also take credit for the birth of a new industry.)

Blanquier seems unfazed by the discontent. “In ministerial meetings, we leave our phones in lockers before going in,” he said in September. “It seems to me that this as doable for any human group, including a class.”